Fuel Rail Heat Soak
 

The problem I have is heat soak on the fuel rail. I put on heat shields for the rail and also replace the one above the exhaust manifold, however if I turn the engine off while shopping etc, the fuel rail heats up to 209 degrees. Which I'm assuming causes vapor in the rail and is very rough engine running when I re-start the engine if it sits for 5 min or so? I can bleed the fuel rail before starting engine and corrects the issue, or I can raise the hood after turning the engine off when it is hot and it corrects the problem. It does not have the return line on the fuel rail. anyone know of a fix. Ive thought about putting a switch on the electric fan and turn it on when I stop the engine until it cools down? is there a thermo switch I could use manually? I'm thinking it's because the engine runs hotter than it should...210-215 on average, but it doesn't over heat? I jus completely rebuilt the engine..new radiator included. Runs great except for this one issue....and I remember it seemed to do the same thing before the rebuild. Rebuilt because #3 piston skirt broke off as common in the 2000 XJ. I have a small amount of coolant loss...maybe a pint in a month..which concerns me, I have not had the head checked for cracks even though there was no indication of this when I cleaned it up during the rebuild...I do not see any bubbling back into the overflow tank...and rocker arms etc very clean...no indication of moisture present... Everything is factory on the engine... no mods

You didn't re-install the original 0331 head on an 00 XJ did you?

Reusing the factory head would have been a mistake. As far as the fuel rail, I run into this on my 2000 as well. It's also a common issue, and like you said it occurs when I restart he Jeep after 5-10 minutes. All I do is give it a little bit of gas to get fresh cool gas in the injectors. Literally takes a second, 2 at the most then it is fine, and I'm only increasing the RPM by a few hundred.

Every time I read about this I wonder why I don't have this problem with my '00. Mne is a CA Emissions one. It ran fine with beat to hell Champion plugs, an old beat up heat shield, and the original injectors. Ran the same with new Champions, 4 hole injectors, and while I was there put on a new heat shield.

I've noticed on my jeep, it's a very specific set of circumstances that it happens under. It only happens during the summer months when I've driven long enough to get the engine to full operating temperature shut the engine off, and then restarted the engine within about 10 minutes. Then it happens. If my Jeep is restarted within a few minutes after shutting it off, no issue. If I let my Jeep sit for 20 minutes, no issue on restart. It only happens when the planets are aligned, and a squirrel has found the biggest nut of the season while escaping from a pursuing Black Labrador.

Injectors not sealing completely after shutting off?